Tube bender



. Sept. 5, 1939.

v. D. BEEHLER ET AL- TUBE BENDER Filed Aug. s, 1936 2 Sheets-Sheet 1 Sept. 5, 1939. v. D. BEEHLER Er'AL TUBE BENDER Filed Aug. 5, 1936 2 Sheets-Sheet 2 INVENTORS Fig 12 Patented Sept. 5, 1939 TUBE BENDER.

Vernon D. Beehler, Evanston, and Robert D. McIntosh, River Forest; 11]., assignors to The Imperial Brass Manufacturing Compa y, Chicago, 11]., a corporation of Illinois Application August 5, 1936, Serial No. 94,478

Claims. (c1. s1

Our invention relates to tools and particularly to manually operated benders for tubes and semifiexible conduit.

The general object of our invention is the provision of a new and improved bender for tubing and conduit.

Another object of our invention is the provision of a single tool for bending tubing of a va- 'riety of sizes.

Another object is to provide a bending tool capable of producing bends of different curvature.

Another object .is the provision of -a single bender capable of producing bends of diflerent curvature in tubing of difierent diameters.

Another object is the production of a new and improved tube bender which when assembled is operable toproduce a bend of any extent up to 180 in either right hand or left hand direction.

A further object is to construct a tube bending tool operated by action of d a pair of levers, the

relative position of which can be changed during a single bending operation to supply the most convenient leverage to the operator.

A still further object of our invention is the provision of a tube bending tool in which parts are locked in place prior to rotation during the bending operation and which can be unlocked at any position of rotation.

Still a further object is to provide a bending tool having two mutually rotatable parts, one of. the parts carrying a projection for engagement with the other operable to lock said parts at the start and during the bending operation and release said parts at the completion of the bend.

Another object is the production or a new and improved tube bender which when assembled is operable to produce a bend of any extent, up to 180 in either right hand or left hand direction.

A further object is to construct a tube bending tool operated by action of a pair of levers, the relative position of which can be changed during a single bending operation .to supply the most convenient leverage to the operator.

A still further object of our invention is thewith any of said bending members.

justing means to fix it in position for operation Another object is to provide a tube bending tool, having mutually rotatable members, one of the members forming a base and having mounted 5 on it a forming block presenting different faces to accommodate tubes of different diameters, the tool being supplied with a series of bending elements of different radii, each positionable on the I base, cooperable with its respective forming block 109 face and capable of being locked in position while making a bend of any fractional part of 180' in either direction and immediately releasable at any position.

In pursuance to the foregoing objects, we aim w to provide a universal bending tool for bending tubes of various sizes into bends of various curvatures. Other objects and advantages will appear as the description proceeds, taken in connection with the drawings which form a part of this 20) specification.

In the drawings:

Fig. 1 is a top view of the preferred form of our invention with the wrench or handle member removed, set up for operation on a large tube.

Fig. 2 is a longitudinal central section of the preferred form of our invention.

Fig. 3 shows the same tool set up for-bending a smaller tube.

Fig. 4 is a side view of the preferred form of so the invention with parts in disassembled position. I

Fig. 5 is a cross section showing the general shape of the grooves in the guide block.

Fig. 6 is a view of the underside. of a guide block used in a modification of our invention. 35

Fig. 7 is a section through the guide block in the modified form showing it suspended ready for clamping into position on the body of the tool.

Figs. 8, 9 and 10 show the bending operation of the modified form at various stages.

Figs. 11 and 12 are front and side views of one of the bending members used in the modified form.

For the purposes of disclosure we have illustrated in the drawings and shall hereinafter describe in detail the preferred embodiment of the invention, together with a modification with the understanding that we do not intend to limit 'our invention to the particular construction and arrangement shown, it being contemplated that various changes may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

An initial consideration when bending semiflexible tubing such as the copper or aluminum tubing used in the refrigeration and automotive industry is the fact that there is a certain minimum diameter smaller than which a tube of a given size cannot be bent without creating kinks or ridges on the inside of the bend. The larger the size tubing the greater this minimum diameter needs to be, taking into consideration of course the thickness of the tubing wall. In opposition is the circumstance that the smallest bend possible is most desirable on some installations and since such is the case a tool is naturally sought which will make a bend as small as possible in diameter for each respective size tubing. Therefore, in order to produce a tool for serving a variety of sizes, features combining variations in groove size for the tube and of curvature for the bend need be considered.

Bending tools for pipe, tubing and conduit have been in general use for some time and many attempts have been made to supply convenient hand tools to perform these operations. Lately the use and application of copper tubing has increased to such an extent that bending tools have been sought which are adapted to the making of neat regular bends in such tubing and which can be conveniently used during the actual installation in cramped quarters at any point along the tubing line. Hence, a hand tool of relatively small size is needed for work of the type noted, necessarily performed on most occasions under conditions which would prohibit the use of bulky tools. A draw back in the production of convenient tools for such work is that even though ductile, copper tubing in the larger sizes requires the exercise of considerable force in bending and especially so when it is desired to make the bend clean and regular. As a consequence relatively heavy tools have been the rule. An additional complicating circumstance is various sizes of tubing are used and hence where a heavy tool is needed for each and every size a sufllcient variety of tools is prohibitive by reason 7 of shear bulk and weight, particularly where they must be carried about from one job to another. The present invention incorporates with other novel structure provision for bending a variety of sizes of tubing with one and the same tool by the alternate substitution of a single variable part.

Accordingly a body I is used for all sizes and carries mounted thereon a variable guide block 2. A variety of different rollers or bending members may be used, a large size member or wheel 4 being shown in position on the body I in Figs. 1 and 2 and a smaller size bending member 5 being shown on the same body I in Figs. 3 and 4. A single wrench member 3 is designed to operate with all sizes of bending members.

On the body I is a perfectly flat upper surface In and opposite it in the other face are formed ribs H for strength and rigidity. One end l2 of the body is made of sufficient size so that it can be drilled out and threaded as at l3 to receive a standard pipe M for a handle. At the end opposite the handle there is a threaded hole l5 extending inward from the flat upper surface I!) which accommodates a clamping arrangement for the block 2. Approximately at the center is a drilled hole IE to be used with larger sizes of bending members and above-it another similar drilled hole I! for the smaller bending members.

Guide block 2 is provided to accommodate tubing of different sizes and in order that it may fit equally well in all positions one face 20 is made perfectly flat so as to ride evenly on the upper that many and ameter 32 is slightly greater than the radius of surface In of the body l. The top surface 2| of the block may also be flat and has provided therein a depression 22 for the purpose of reducing the weight of this member. Formed on the edge of the guide block are the grooves whose function it is .to guide the pipe, tubing or conduit. To assist in describing the tool the pipe or tubing so operated upon will be termed the work". The description will be first concerned with groove 23, shown on the lower edge of the guide block in Figs. 1 and 2. The groove is used with the largest size tube for which the tool is designed and cooperates with the bending member 4. On the edge of the guide block directlyopposite is the groove 24 used with a next smaller size bending member. At the right edge as viewed in Fig. 1 is the groove 25 cooperable with bending member 5 for smaller tubing, or for tubing to be bent on a smaller radius and, on the edge 26, opposite 25, is still another groove making four grooves in all for this particular embodiment of the invention.

Extending completely around the block 2 is a.

rim or lip 21 having'an inside surface 28. The surface 28 is always a uniform distance from the rear face 20 of the block providing a recess of uniform height when the block is mounted in place on the upper surface ID of the body.

In order to prevent reduction in capacity of a tubing line when installed it is desirable to have the section remain circular after a length of tube has been bent. To secure this the grooves 23, 24,

25, and the groove on the edge 26 are shaped in the form of a semi-ellipse, similar to that shown in the fragmentary section of groove 24 in Fig. 5.

The minor diameter 29 is equal to the diameter of the particular tube 30 for which it is designed and the edges 3| are rounded off to freely admit the tube into the groove. The semi-major dithe tube 30 so that the tube during a part of the bending operation is distorted in cross section for reasons which will be noted later.

In the central portion of the block 2 are holes 33,34 and drilled clear through to the face 20. These holes are for the reception of a screw 35 carried by the clamping wheel 31 by means of which the block is held in place. The screw 36 is threaded at the end to fit into hole IS in the body and can be shifted from one to another of the holes 33, 34 and 35 as occasion requires. The screw is shown with a pilot end 38 for guiding the member into the hole l5.

Bending is done around the member 4 or the member 5, or other similar members not shown. whose diameters may be varied to suit the corresponding position of the block 2 and the size of the particular tube being worked. Since the principal of operation is identical in each'case The face ll of the bending member or wheel adjacent the upper surface of the body I is flat to permit the member to ride evenly upon the body. The curved rim of the bending member I is grooved in the form of a semi-circular section 43 large enough to accommodate a piece of tubing N. The groove extends around the curved edge of the member from one end of the fiat edge 40 to the other, an angular distance in excess of Uniformly disposed about the center of the bendingmember are pairs of holes 45 cooperable with the wrench member 3.

At the center of the bending member 4 is a loose pin arrangement for positioning the member on the body. A hole 45 is drilled part way through and a smaller hole 41 is drilled through the remainder of the section, forming at the junction of the two a shoulder 45. Concentric within the holes a pin 49 is positioned which has a large end 50, bevelled so as to slide easily into the hole l of the body and having a neck 5| of reduced diameter extending through the hole 41 and forming an annular ofiset 52 with the large end. The pin is capped with a knurled thumb grip 53. By reason of the play between the shoulder 45 in the member 4 and offset 52 on the pin, the latter may be pulled out toward the left until the bevelled end clears the surface ID of the body. Complete removal is prevented by abutment of the offset 52 against the shoulder 48. When the bending member is in the proper position the pin 49 is pushed toward the right and enters hole l5. Contact of the lower edge of knurled thumb grip 53 with the upper surface of the bending member limits the plug-in motion of the pin and provides a convenient grip for removing it when necessary. On the flat edge 45 of the bending member there is an arm54 pivoted at 55 and having a hook 55 at the end for grasping the tube 44.

For cooperation with the bending member or wheel 4 the wrench member 3 has a body 50 fitting fiat against the bending wheel. The body has a boss 6| threaded at 52 for reception of a length 53 of standard iron pipe to serve as a handle. There is a central hole 54 large enough to slip easily over the knurled thumb grip 53 and a pair of pins 55 securely set in the body for contact with the bending member. Pins 55 are spaced oppositely to correspond with any of the pairs of holes 45 in the bending member 4 into which the pins may be placed in order to set the wrench member at any of several desired angles, as shown in. Figs. 2 and 3.

Bending member 5 next considered has a groove 55 in the rim of such a diameter as will fit a smaller tube 51 and cooperates with the groove 25 in'the block 2. This member has. a hook 55 shorter than the hook 54, for grasping the smaller tube. A central pin 59 is identical with the pin 49 of the member 4 and operates in the same manner. The member 5 has also pairs of holes not visible, which cooperate with the pins 55 of the wrench member.

There are also to be provided forthis embodiment of our invention two other bending members, one of an intermediate diameter and having its rim grooved to correspond with the groove 24 of the block 2 'and the other having a diameter the same as the member 5; but having its rim grooved similar to the edge 25 of the guide block. Since all the bending members function precisely like member 5 or member 4, a detailed description of them is deemed superfluous. v

To bend a tube of the largest diameter the tool is set up as in Figs. 1 and 2. The block 2 is fastened to the body I by inserting the screw 35 in hole 33 and screwing it down reasonably tight against the body. Tube 44 is then placed in the I groove 23. The bending member 4 is laid on the upper surface ID of the body with the central pin 49 pushed back into the hole 45 so as to clear the face 4| of the bending member. From this position the member is slid along the face ID of the body against the tube 44 and against the block 2. I

' suiting cl'oss-section-is practically circular.

of the block and the edges of the bending member in each case so that should a tube be out of round or have a diameter slightly oversize there would still be room for the bending member to be pushed ,into place and permit the pin 49 to properly drop into the hole l5. The combined action of the pin 49 centering the member and the lip 21 holding it tight against the body serves to effectively lock the tool together. With the parts in place the hook 55 is swung over the tube to grip it for the bend. Wrench member 3 is dropped into place at the desired angle and by pulling the handles a bend is formed by the action of drawing the tube through the groove 23 and forcing it against the curved outer groove of the member 4. The member can be rotated as much as 180 for making a U shaped bend in either direction from the same set up, and should occasion require an initial bend of an excess of 180 may be made. A bend in excess of 180 will of course necessitate springing the tube in order to release it from the bending wheel.

When the desired bend is made, which may be a U shaped bend or anything less, the tool is separated by withdrawing the pin 49, using the knurled thumb grip 53, thereby immediately releasing the member 4 from its locked position on the body. The bent tube being thereby freed will fall out of the groove.

Asa. tube is bent there is a tendency for the cross section to become flat at the outer side of the bend thus reducing the cross section area and consequently the capacity of the tube. To eliminate this the grooves in the forming block may be made semi-elliptical as previously noted. As a consequence the tube is drawn into an eggshaped cross-section as it makes contact with the guide block groove but the subsequent stretching tendency resulting from the pull on the tube as it is pressedagainst the curved groove pulls the, egg-shaped cross-section down, so that the re- It is not always essential to distort the semi-circular shape of the groove 43 in the other member 4 because the .pressure on the tube tends to force it into the groove and mold it to the desired shape.

To bend a tube of the size used in groove 24 of the guide block 2 the screw 35 is loosened slightly and the block swung end for end to present groove 24 to the work where it is tightened in place.

Then a bending member similar to member 4 in every respect except for diameter and size of H in the body is substituted in order to have the member 5 in the proper position against the tube 51. For a bending operation using the edge 25 of the block another member not shown but corresponding in size to member 5 is made use of.

The groove in the edge of this member will be still smaller than groove 25 corresponding in size to a small groove in the block 25. When bending pressure is put upon the tube by means of the hook the block is likely to shift slightly as in Fig. 3 due to the pressure of the tube against the block at the end of the groove. The shifting movement causes the block to adjust itself centerably so that the maximum pressure is more nearly against the mid-section of the groove. Thus an ample clearance can be allowed between the block and bending member so that the tool will adjust itself to tubes which may be considerably out of size. -Bending members of different outside diameters are a convenience in order to get the minimum bend for tubing of a given size without danger of kinking the tube on the inside of the bend.

The modification illustrated in Figs. 6 to 12 involves a novel locking arrangement comprising a minimum of moving parts. In this modification the forming block is held stationary. The arrangement comprises a body member18 similar in general construction to the body I having a flat upper surface 1| and provision for a pipe handle 12. There is a central aperture 13 and slots 14 extending angularly therefrom, terminating preferably in apertures 15. At the upper end are set a pair of pegs 18 on either side of a hole 11.

A forming block 88 has its edges grooved at 8|, 82 and 83 for tubes of different diameters. The bottom surface 84 fits flat against the body 18 and the top surface 85 extendsbeyond the grooves and forms an overhanging lip 88. Underneath the lip at each edge and above the. groove a circular section has been cut to correspond approximately with the curvature of a bending member such as the member 81, the sections being 88, 89 and 98 to correspond respectively'with bending members of different size and the respective grooves at 8|, 82 and 83. The purpose of these sections is to prevent the bending members, such as 81 from shifting laterally or away from the flat face of the body once in a central locked position. On the bottom face .of the block 84 are two sets of depressions 9i and 92, which are spaced and sized to fit alternately over the pegs 18. Through the central part of the block is a slot 98, one end 94 of which is positioned midway between the depressions 9|, the other end 95 being midway between the depressions 92. For holding the block in place a bolt 98 and hand screw 91 are provided.

When, for example, it is desired to set the block 84 in the position shown In Figs. 8, 9 and 10 the end 94 of the slot 93 is used. In this case the corresponding depressions 9|, equidistant from the end 94, fit over the pegs 16, (seeFig. 8). The hand screw 91 is used to tighten the block in place and the block will present edge 82 to the work. Should it be desired to change the block in order to use edge 8| for example, the hand screw should be loosened sufficiently to allow the block to be lifted high enough so that the bottom face 84 will clear the pegs 16. In the raised position the block is swung end for end bringing the grooved edge 8| to the work. For this latter reversed position the same end 94 of the slot and the same depressions 9| are again utilized. The third position forwhich this modification is designed is attained by shifting the block so that the groove on edge 83 is facing the work. Again the hand screw 91 is loosened and after the block is lifted clear of the pegs it is turned so that the edge 83 faces. the center of the tool. In this general position the block is shifted in a slightly angular direction endwise made necessary by the bolt 96 traveling along the slot 93 to the opposite end 95. In this third position the depressions 92 fit over thepegs 18, and the block is clamped in place. By the movement described the edge 83 is brought near enough to the center so that the groove of a bending member of smaller diameter will be adjacent the block although being used in the central aperture 13.

The bending member 81 above referred to has an arm l8l'pivoted at IM and equipped with a pair of hooks I82 for grasping a tube I83 from either side. Disposed about the center are pairs of holes I84 for cooperation with the wrench member 3, as previously described, and around the outer edge is a groove I85 in which the tubing is bent. The bending member used in the modification differs from that in the preferred formby having a fixed pin I88 at the center. On one side of the pin is a flat surface I81. The width across the pin at the center of the flat is sufliciently narrow to allow the pin to slide freely along either of the slots 14.

In assembling the tool for a bending operation the block 88 is set in position on the body as described. The edge 82 is used when the bending is to be done with the member 81 as shown. A tube I83 is placed in the groove and bending member 81 is rested on the body 18- with the pin I88 extending into one of the apertures 15. The member is then rotated until the flat side I81 of the pin occupies a position as shown in Fig. 8 from which it is slid along the slot 14 to the centralaperture 13, in the direction of the'arrow. For a left hand bend the member is rotated to the position shown in Fig. 9 where the member is effectively locked in place by rotation ready for the bend. Then with one of the hooks I82 in place the member is rotated to the position shown in Fig. 10, making a U shaped bend shown by the dotted position of the tube I83. At this point the hook I82 is lifted from contact with the tube. By continuing the rotation a short angular distance further in the direction shown by the arrow a position will be reached wherein the flat I81 on the pin will be facing the lower side of the right hand slot 14. The pin can then be slid down slot 14 carrying with it the member 81 and the bent tube, completely released from contact with the block 88. It will be apparent that by use of the right hand slot 14 the tool may be unlocked without turning it clear back to the starting position. The action of the cut out section 88 in the block, restraining lateral movement will prevent the pin sliding down the slot in reverse position to unlock the parts before the U shaped bend has been completed. It will be further apparent that any bend less than a complete U can be made and the device similarly unlocked to extract the tube. Either a complete right or complete left hand bend can be made from the same set up without removing the bending member, also the hook I82 as a matter of .convenience can always be dropped downward into engagement with the tube. As an added advantage the block 88 need never be' removed from the tool for any change in operation and is therefore unlikely to be lost or misplaced.

Having thus described our invention what we claim and seek to secure by Letters'Patent is:

1. A bending device for conduit comprising a body having a working surface, a guide element for the conduit operative during bending including a block having recess means at the edge thereof wherein the conduit is guided during bending and means for attaching the element to the surface of the body, a curved bending member for the conduit separable from the body including conduit holding means and recessed edge portions for determining the curve of the conduit, said bending member being engageable with the guide element, and means for rotatably securing the bending member to the body comprising an aperture in one part and an axially said pin connection being cooperable upon engagement of the guide element and the edge portions of the bending member to releasably interlock the bending member with said guide element and the body during a bending operation in either direction. I

2. A bending device for conduit comprising a body, a guide element for the conduit including a block having a recess wherein the conduit is guided during bending and means for attachingthe element to the body, a'curved bending memher for the conduit separable from the body,

7 including, conduit holding means and recessed edge portions for determining the curve of the conduit, said bending member being .engageable with the guide'element at the recess, and means for rotatably securing the bending member to the body comprising an aperturein one part and an axially movable loose pin element receivable therein located in the other part, saidlast part having an engaging portion and said pin element having a pair of engaging portions cooperable' therewith to permit movement of said pin element a limited distance into the apertureto releasably interlock the body and bending member in conduit bending relation with the guide element and to permit withdrawal of the pin element to a limited position out of contact with the aperture to release said parts.

3. A bending device for conduit comprising a body having a working surface, a guide element for the conduit including a block having a recessed portion wherein the conduit is guided during bending and means for attaching the element .to the surface of the body, a curved bending means for the conduit separable from the body, including conduit holding means and conduit receiving means for determining the curve of the conduit when bent in either direction by the device, said bending means-being ,engageable with the guide element, pin and aperture means being engageable to prevent a lateral shift of the bending means with respect to the body element and cooperable with the guide element in turn of the pin therealong only when the pin presents the flat thereon to one side of the slots, said pin when at the'ioined end of the slots being cooperable with the bending means, the guide element and the body to form a rotatable interlock during bending of the conduit and being rotatable to a position for release of the bending means after bending for the extraction of bent conduit.

'4. A bending device for conduit comprising a body having a working surface, a guide element for the conduit including a block having a recessed portion wherein the conduit is guided during bending and means for attaching the element to the surface of the body, curved bending means for the conduit including conduit holding means and conduit receiving means for determiningthe curve oi the conduit when bent in either direction by the device engageable with the, guide element, and pin and aperture means cooper-able with the guide element for rotatably locking the bending means to the body comprising a pin in one part having a reduced portion thereon forming a narrow dimension, and in the other part a slot disposed angularly with respect to the recessed portion of, the block having at one portion thereof a substantially circular aperture of a diameter to permit rotation of the pin, said slot being oi a width to permit translation of the pin therealong only when the pin presents its narrow dimension across the slot, said pin and the sides of said circular aperturebeing cooperable upon engagement of the bending means with the guide element to form a rotatable interlock during the bending and being positionable rotatably toallow release of the bending means after bending for the extraction of bent conduit.

5. A conduit bending device comprising a body member, a. conduit guiding means carried by said member having contact with one side of the conduit, a bending member having a groove thereon for contacting the other side of the conduit and means for holding the conduit, centering means for releasably securing said body member and bending member together in conduit bending position, a plurality of sets of wrench engaging holes on one of said. members, one set being operative in each of several positions of the memcentering means to permit shifting said means manually so that said one member may be retained attached to the wrench member while being removed from the other member and the wrench member used to assist in forcing the bent conduit from the device.

VERNON D. BEEI-ILER. ROBERT DJMCINTOSH. 

